Lady Macbeth speaks these words in Act 1, scene 5, lines 36–52, as she awaits the arrival of King Duncan at her castle. We have previously seen Macbeth’s uncertainty about whether he should take the crown by killing Duncan. In this speech, there is no such confusion, as Lady Macbeth is clearly willing to do whatever is necessary to seize the throne. Her strength of purpose is contrasted with her husband’s tendency to waver. This speech shows the audience that Lady Macbeth is the real steel behind Macbeth and that her ambition will be strong enough to drive her husband forward. At the same time, the language of this speech touches on the theme of masculinity— “unsex me here / . . . / . . . Come to my woman’s breasts, / And take my milk for gall,” Lady Macbeth says as she prepares herself to commit murder. The language suggests that her womanhood, represented by breasts and milk, usually symbols of nurture, impedes her from performing acts of violence and cruelty, which she associates with manliness. Later, this sense of the relationship between masculinity and violence will be deepened when Macbeth is unwilling to go through with the murders and his wife tells him, in effect, that he needs to “be a man” and get on with it.

In this soliloquy, which is found in Act 1, scene 7, lines 1–28, Macbeth debates whether he should kill Duncan. When he lists Duncan’s noble qualities (he “[h]ath borne his faculties so meek”) and the loyalty that he feels toward his king (“I am his kinsman and his subject”), we are reminded of just how grave an outrage it is for the couple to slaughter their ruler while he is a guest in their house. At the same time, Macbeth’s fear that “[w]e still have judgement here, that we but teach / Bloody instructions which, being taught, return / To plague th’inventor,” foreshadows the way that his deeds will eventually come back to haunt him. The imagery in this speech is dark—we hear of “bloody instructions,” “deep damnation,” and a “poisoned chalice”—and suggests that Macbeth is aware of how the murder would open the door to a dark and sinful world. At the same time, he admits that his only reason for committing murder, “ambition,” suddenly seems an insufficient justification for the act. The destruction that comes from unchecked ambition will continue to be explored as one of the play’s themes. As the soliloquy ends, Macbeth seems to resolve not to kill Duncan, but this resolve will only last until his wife returns and once again convinces him, by the strength of her will, to go ahead with their plot.

Macbeth says this in Act 2, scene 2, lines 55–61. He has just murdered Duncan, and the crime was accompanied by supernatural portents. Now he hears a mysterious knocking on his gate, which seems to promise doom. (In fact, the person knocking is Macduff, who will indeed eventually destroy Macbeth.) The enormity of Macbeth’s crime has awakened in him a powerful sense of guilt that will hound him throughout the play. Blood, specifically Duncan’s blood, serves as the symbol of that guilt, and Macbeth’s sense that “all great Neptune’s ocean” cannot cleanse him—that there is enough blood on his hands to turn the entire sea red—will stay with him until his death. Lady Macbeth’s response to this speech will be her prosaic remark, “A little water clears us of this deed” (2.2.65). By the end of the play, however, she will share Macbeth’s sense that Duncan’s murder has irreparably stained them with blood.

These words are spoken by Lady Macbeth in Act 5, scene 1, lines 30–34, as she sleepwalks through Macbeth’s castle on the eve of his battle against Macduff and Malcolm. Earlier in the play, she possessed a stronger resolve and sense of purpose than her husband and was the driving force behind their plot to kill Duncan. When Macbeth believed his hand was irreversibly bloodstained earlier in the play, Lady Macbeth had told him, “A little water clears us of this deed” (2.2.65). Now, however, she too sees blood. She is completely undone by guilt and descends into madness. It may be a reflection of her mental and emotional state that she is not speaking in verse; this is one of the few moments in the play when a major character—save for the witches, who speak in four-foot couplets—strays from iambic pentameter. Her inability to sleep was foreshadowed in the voice that her husband thought he heard while killing the king—a voice crying out that Macbeth was murdering sleep. And her delusion that there is a bloodstain on her hand furthers the play’s use of blood as a symbol of guilt. “What need we fear who knows it when none can call our power to account?” she asks, asserting that as long as her and her husband’s power is secure, the murders they committed cannot harm them. But her guilt-racked state and her mounting madness show how hollow her words are. So, too, does the army outside her castle. “Hell is murky,” she says, implying that she already knows that darkness intimately. The pair, in their destructive power, have created their own hell, where they are tormented by guilt and insanity.

These words are uttered by Macbeth after he hears of Lady Macbeth’s death, in Act 5, scene 5, lines 16–27. Given the great love between them, his response is oddly muted, but it segues quickly into a speech of such pessimism and despair—one of the most famous speeches in all of Shakespeare—that the audience realizes how completely his wife’s passing and the ruin of his power have undone Macbeth. His speech insists that there is no meaning or purpose in life. Rather, life “is a tale / Told by an idiot, full of sound and fury, / Signifying nothing.” One can easily understand how, with his wife dead and armies marching against him, Macbeth succumbs to such pessimism. Yet, there is also a defensive and self-justifying quality to his words. If everything is meaningless, then Macbeth’s awful crimes are somehow made less awful, because, like everything else, they too “signify nothing.”

Macbeth’s statement that “[l]ife’s but a poor player / That struts and frets his hour upon the stage” can be read as Shakespeare’s somewhat deflating reminder of the illusionary nature of the theater. After all, Macbeth is only a “player” himself, strutting on an Elizabethan stage. In any play, there is a conspiracy of sorts between the audience and the actors, as both pretend to accept the play’s reality. Macbeth’s comment calls attention to this conspiracy and partially explodes it—his nihilism embraces not only his own life but the entire play. If we take his words to heart, the play, too, can be seen as an event “full of sound and fury, / Signifying nothing.”